Fluspidine


Fluspidine is a fluorine-18 labeled radiotracer used in positron emission tomography scans to image σ1 (sigma-1) receptors in the brain and other tissues. Sigma-1 receptors are proteins involved in many neurological and psychiatric processes. They have been linked to pain modulation, psychosis, Alzheimer's disease, and depression.

Chemical properties

Fluspidine is a small organic compound with a spirocyclic structure. A 2-fluoroethyl group on the molecule carries the fluorine-18. The compound exists as two mirror image enantiomers, called -fluspidine and -fluspidine. These enantiomers have slightly different properties: -fluspidine has about 4-fold higher affinity for the σ₁ receptor than -fluspidine, but -fluspidine is metabolically more stable in the body.